Sprocket barrel



I. MARKS.

SPROCKET BARREL. APPLICATION FILED MAY H, 1921.

1,411,926. Patented 1 11,1922.

UNITED STATES PATENT OFFICE.

Isxnomr. MARKS, or rosron, MASSACHUSETTS.

SPROCKET BARREL.

. Application filed May 14,

certain new and useful Improvements in Sprocket Barrels; and I do hereby declare the following to bea full, clear, and. exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same;

.This invention relates to film feeding mechanism for motion picture machines and more particularly to the construction of a sprocket barrel used in such mechanisms for enga ing the feed holes in the margins of the. 1m. p ,v p

The sprocket barrel of the present inven tion isespecially adapted for use in toy motion picture machines of the type disclosed in Letters Patent of the United States No. 1,3&5 ,793 granted to the present inventor July 6,1920. In the machineof said patent the feed mechanism includes a pair of sprockets at the ends of a barrel, spaced to engage the lines of feed holes in the film,

with an attached star wheel of a Geneva motion to impartan intermittent rotary motion improve the construction of the sprocket barrel to give it strength-and great durability, while increasing its efiiciency due to an improved and more efiicient manner of sembling the elements which insures their proper relation to each other and increases the life of the mechanism. The improved construction also provides for a more eflicient lateral support of the film as it is fed through the machine,

. To thej-accom pli hment of this v object I and such others as may hereinafter appear,

as will be readily understood by those skilled inf the art, theinvention comprises the featuresf and combinations of parts hereinafter described and then particularly pointed out in therclaims.

The preferred formof the invention is illustrated inthe accompanying draw- I ings, in which Figure 1 is an end view of the sprocket barrel, Fig. 2 is a longitudinal section on the line 2-2 of Fig.

1, Fig. 3 is a perspective view of the bearing on which the feed motion parts are mounted, and Figs. 4 and 5 are two partial Specification of Letters Patent.

Patented Apr. 4, 1922.

1921. Serial No. 469,743.

sections, showing steps in the method of securing the parts on the bearing.

It has been customary heretofore to form the sprocket barrel of toy motion picture machines, of the type disclosed in said patent, from sheet metal and to solder the Geneva star wheel at one end. Difliculty has been found with this method of construction in properly aligning the sprockets and. stably securing the parts together. In addition to this difficulty it has been impossible to give the moving film sufficient lateral support to prevent its buckling to such an extent as to tear the margins from the sprocket wheels and otherwise interfere with the required continuous feed thereof.

. In the embodiment of the invention illustrated in the drawings the mechanism comprises separately manufactured parts which are assembled in the exact required. relation on a bearing whlch is mounted for rotation on astationary shaft carried by the frame of the motion picture machine. The bearing is formed with a cylindrical portion 6 with integral, reduced end portions 7 and 8, the end 7 being longer than the end 8. Each end portion is cylindrical except for a flat side 9 and 10 formed by slabbingoff a portion of the material, all as shown in Fig. 3. The bearing is provided with an axial bore 11 for the reception of the shaft hereinbefore referred to. The reduced ends? and 8 form shoulders 12 and 13 against which the two sprocket wheels 1 1 and 15 bear. The

length of the bearing portion 6 is such that when the sprocket wheels are engaged with the shoulders the wheels will be the correct distance apart to properly engage the feed holes in the margins of the film. Each sprocket is provided with a central aperture of the same shape as the cross-section of the reduced ends 7 and S, such that they are constrained to rotate with the bearing and cannot move relatively thereto. On the longer reduced end 7 of the bearing there is mounted a spacing collar 16 and the star wheel 17 of a Geneva motion through which the barrel is rotated. The parts 16 and 17 are held from movement relatively to the bearing in the same manner as the sprockets. Between the sprockets there is: seated on the bearlng a spool 18 of the same length as the enlarged portion 6 of the bearing andof such diameter as to efiiciently support the film, being advanced by the sprockets, in a lateral direcrequired to properly support the ll tion to prevent buckling and consequent interference with the feed.

The v ions features of the sprocket barrel just described are manu lectured as separate elements from suitable material. Preferably the hearing will be of steel, the sprockets and Geneva star wheel of brass and the spool of wood. After the driving elements have been assembled on the bearing in the relation shown in Fig. 2, they are secured in place in the following manner.

The type of machine in which the sprocketharrel is used is provided with an opening in the ame which admits the entry of the barrel with a close lit, thus prcventiir endwise movement of the barrel on the supporting shaft and assembling it in exact relation to the driving element of the Geneva motion. It is requisite, therefore, that the elements of the barrel be secured on the bearing in such manner that its length is not increased by the securing means.

To this end the reduced bearing extensions l I and 8 are preferably not longer than 1s lm driving elements. Each end of the her in is then countersunk, as shown at 19 Ll), by any convenient rotary cutting tool indicated at 20. The counter-sinking operation reams away'the end of the bearing slightly within the outer face of the elements at the ends thereof. In Fig. i the showing of this operation is exaggerated since in practice the countersink angle is very slight and the cutting away of the bearing end is not deeper than fivethousandths of an inch. The countersunk ends of the hearing are then out into and the outer rim 21 (Fig. thus formed is forced outwardly and pressed into the softer adjacent contacting metal of the driving elements, producing flanges which hold all of said elements securely in position against the spacing shoulders 12 and on the hearing. The tool for performing this operation is indicated at 22, being provided with a central guide 23 and a cutting edge 24 having a peripheral shape like that of the central apertures in the film driving elements so as to produce a continuous outer rim 21. The cutting edge of the tool, as it enters the bearing ends, flanges said ends inside the end faces of the barrel. As best shown in Fig. 2, the completed sprocket barrel has flush ends, the over-alhlength thus being not greater than the length of the opening in. the frame in which the barrel is seated when the machine is assembled.

The nature and scope of the invention having been indicated and the preferred embodiment of the invention and method of assembly having been specifically described what is claimed as new, i.

1. A sprocket barrel for motion picture machines comprising a bearing having a shoulder adjacent each end, a pair of sprockets abutting said shoulders for engaging the lines of feed holes in the film, a spool on said bearing between the sprockets to give lateral support to the film, and means for securing said sprockets against rotation on the bearing.

2. A sprocket barrel for motion picture machines comprising a cylindrical bearing having reduced ends, one of said ends having a sprocket supported thereon, and the other end having a-sprockct and a Geneva motion star wheel supported thereon, said ends and elements being so constructed and arranged as to prevent rotation on the bearing, and a spool on the bearing between said sprockets.

3. A sprocket barrel. for motion picture machines comprising a bearing having a cylindrical central portion and reduced ends each of which has a fiat side, a sprocket on each end having a central aperture shaped to lit the end, a Geneva motion star wheel having a like central aperture on one end adjacent the sprocket thereon, and means to hold said. elements in position on. said ends.

4:. A sprocket barrel for motion picture machines comprising a bearing, a pair of sprockets non-rotatably fixed on the bearing, means on the bearing to space the sprockets apart a distance equal to the distance between the feed holes in the film, a Geneva motion star wheel non-rotatably fixed on the bearing, and flanges at the ends of the bearing to hold said elements in position.

5. A sprocket barrel for motion picture machines comprising a bearing having a reduced ends forming spaced shoulders, film driving elements seated on said reduced ends, the length of said ends being substantially equal to the thickness of the parts seated therein, and means at each end. face of the bearing located within the outer end faces of said elements for securing said elements against said shoulders on the bearing, whereby the barrel has flush ends.

6. A sprocket barrel for motion picture iachines comprising a bearing of hard metal. film driving elements of softer metal non-rotatably seated on the ends of the bearing, and flanges at the ends of the bearing turned outwardly into the softer metal of the driving elements and within the outer faces of said elements.

7. The method of assembling motion picture machine sprocket barrels which comprises forming a bearing of hard metal, seating film driving elements of softer metal on the ends thereof, countersinking the ends of the bearing to insure flush end faces on the barrel, and forcing the peripheral portion of said countersunk ends into the adjacent contacting metal of the driving elements.

8. The method ofassembling motion picture machine sprocket barrels which comprises providing, a bearing with reduced ends forming spaced shoulders, seating film ture machine sprocket barrels which com- 10 driving elements on said ends, removing any prises assembling film driving elements on portion of the bearing ends projecting bethe ends of a bearing formed with shoulyond the end faces of said driving elements, ders to space said elements apart, and secur- 5 and seating said elements against said sh0uling said elements against said shoulders by ders by forcing the ends of said bearing outcountersinking the, ends of the bearing and 15 Wardly against the adjacent contacting porthen fianging said ends inside the end faces tions 01: the driving elements. e of the driving elements.

9. The method of producing motion pic- ISIDORE MARKS. 

